Just thought I'd share my experience with propecia, since I'm a runner and actually perused the threads on here about propecia before giving it a try.
Background - I first noticed my hairline receding ever so slightly at 25, but it was never enough to bother me, not really even noticeable. Around 30, i grew my hair out to shoulder length, and i have to say, it looked f'ing awesome. I was getting random girls on the street or working at coffee shops, etc, telling me i was handsome.
Then the bomb dropped. One day at home, my gf told me i was thinning around the crown. Mortified at the potential of losing my locks, i researched what i could do. The only things that seemed not to be snake oil and had actual proof of effectiveness were propecia and rogaine. I immeduately started rogaine and went to the doc for a propecia prescription. He assured me it was safe and if i hadn't already had problems downstairs i should be fine. When i got home, i googled it just to be sure, and i find all the horror stories that you find when you google 'propecia side effects'. I decided to stick with the rogaine for the time being, and it did work to thicken up my crown, so i didn't worry about it.
About a year later, however, i started to shed like crazy, so i bit the bullet and started propecia. I was cautious, only taking half a dose 3x per week. After a week, i was happy - no side effects sexually or in the gym, so i was thinking i could stay on it indefinitely and keep my hair. After about 3 weeks, however, i was with my girlfriend and i felt like my penis had been shot up with anaesthetic. I could still have an erection, but i felt nothing. I immediately stopped taking it, but this went on for about 2 terrifying weeks. Finally, after about a month it cleared up.
Anyway, my point is that it is not a completely harmless drug,. I really understand the desire to want to hang on to your hair, but be very careful - you are playing with a very potent hormone and.no one knows all the things.this can do over the long term.